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Flashcards in Neurology - Pathology Deck (30)
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1
Q

Dementia

  • Description
  • Most common causes
  • Other causes
A
  • Description
    • A decrease in cognitive ability, memory, or function with intact consciousness.
  • Most common causes
    • Alzheimer disease
    • Pick disease (frontotemporal dementia)
    • Lewy body dementia
    • Creutzfeldt-Jakob disease
  • Other causes
    • Multi-infarct (2nd most common cause of dementia in elderly)
    • Syphilis
    • HIV
    • Vitamins B1, B3, or B12 deficiency
    • Wilson disease
    • NPH.
2
Q

Alzheimer disease

  • Type of condition
  • Description
  • Histologic / gross findings
A
  • Type of condition
    • Dementia
  • Description
    • Most common cause in elderly.
    • Down syndrome patients have an increased risk of developing Alzheimer.
    • Familial form (10%) associated with the following altered proteins (respective chromosomes in parentheses):
      • Early onset: APP (Chr 21), presenilin-1 (Chr 14), presenilin-2 (Chr 1)
      • Late onset: ApoE4 (Chr 19)
    • ApoE2 (Chr 19) is protective.
  • Histologic / gross findings
    • Widespread cortical atrophy.
    • Narrowing of gyri and widening of sulci
    • Decreased ACh
    • Senile plaques [A]
      • Extracellular β-amyloid core
      • May cause amyloid angiopathy –>Ž intracranial hemorrhage
      • Aβ (amyloid-β) synthesized by cleaving amyloid precursor protein (APP)
    • Neurofibrillary tangles
      • Intracellular, hyperphosphorylated tau protein = insoluble cytoskeletal elements
      • Tangles correlate with degree of dementia
3
Q

Pick disease (frontotemporal dementia)

  • Type of condition
  • Description
  • Histologic / gross findings
A
  • Type of condition
    • Dementia
  • Description
    • Dementia, aphasia, parkinsonian aspects, change in personality.
    • Spares parietal lobe and posterior 2 ⁄3 of superior temporal gyrus.
  • Histologic / gross findings
    • Pick bodies: spherical tau protein aggregates
    • Frontotemporal atrophy
4
Q

Lewy body dementia

  • Type of condition
  • Description
  • Histologic / gross findings
A
  • Type of condition
    • Dementia
  • Description
    • Initially dementia and visual hallucinations followed by parkinsonian features.
  • Histologic / gross findings
    • α-synuclein defect
5
Q

Creutzfeldt-Jakob disease

  • Type of condition
  • Description
  • Histologic / gross findings
A
  • Type of condition
    • Dementia
  • Description
    • Rapidly progressive (weeks to months) dementia with myoclonus (“startle myoclonus”).
  • Histologic / gross findings
    • Spongiform cortex
    • Prions (PrPc –>Ž PrPsc sheet [beta-pleated sheet resistant to proteases])
6
Q

Multiple sclerosis

  • Definition
  • Presentation
  • Findings
  • Treatment
A
  • Definition
    • Autoimmune inflammation and demyelination of CNS (brain and spinal cord).
    • Relapsing and remitting course.
    • Most often affects women in their 20s and 30s
    • More common in whites.
  • Presentation
    • Patients can present with:
      • Optic neuritis (sudden loss of vision resulting in Marcus Gunn pupils)
      • Internuclear ophthalmoplegia
      • Hemiparesis
      • Hemisensory symptoms
      • Bladder/bowel incontinence
    • Charcot classic triad of MS is a SIN:
      • Scanning speech
      • Intention tremor (also Incontinence and Internuclear ophthalmoplegia)
      • ƒƒNystagmus
  • Findings
    • Increased protein (IgG) in CSF.
    • Oligoclonal bands are diagnostic.
    • MRI is gold standard.
    • Periventricular plaques [A] (areas of oligodendrocyte loss and reactive gliosis) with destruction of axons.
    • Multiple white matter lesions separated in space and time.
  • Treatment
    • β-interferon, immunosuppression, natalizumab.
    • Symptomatic treatment for neurogenic bladder (catheterization, muscarinic antagonists), spasticity (baclofen, GABA receptor agonist), pain (opioids).
7
Q

Acute inflammatory demyelinating polyradiculopathy

  • Definition
  • Findings
  • Associated with…
  • Treatment
A
  • Definition
    • Most common variant of Guillain-Barré syndrome.
    • Autoimmune condition that destroys Schwann cells Ž–> inflammation and demyelination of peripheral nerves and motor fibers.
    • Autonomic function may be severely affected (e.g., cardiac irregularities, hypertension, or hypotension).
    • Almost all patients survive
    • The majority recover completely after weeks to months.
  • Findings
    • Results in symmetric ascending muscle weakness/paralysis beginning in lower extremities
    • Facial paralysis in 50% of cases
    • Increased CSF protein with normal cell count (albuminocytologic dissociation). 
    • Increased protein –>Ž papilledema.
  • Associated with…
    • Infections (Campylobacter jejuni and CMV)
    • –>Ž Žautoimmune attack of peripheral myelin due to molecular mimicry, inoculations, and stress, but no definitive link to pathogens.
  • Treatment
    • Respiratory support is critical until recovery.
    • Additional treatment: plasmapheresis, IV immune globulins.
8
Q

Other demyelinating and dysmyelinating diseases

  • Progressive multifocal leukoencephalopathy
  • Acute disseminated (postinfectious) encephalomyelitis
  • Metachromatic leukodystrophy
A
  • Progressive multifocal leukoencephalopathy
    • Demyelination of CNS due to destruction of oligodendrocytes.
    • Associated with JC virus.
    • Seen in 2–4% of AIDS patients (reactivation of latent viral infection).
    • Rapidly progressive, usually fatal.
    • Increased risk associated wtih natalizumab.
  • Acute disseminated (postinfectious) encephalomyelitis
    • Multifocal perivenular inflammation and demyelination after infection (commonly measles or VZV) or certain vaccinations (e.g., rabies, smallpox).
  • Metachromatic leukodystrophy
    • Autosomal recessive lysosomal storage disease, most commonly due to arylsulfatase A deficiency.
    • Buildup of sulfatides –> impaired production of myelin sheath.
    • Findings: central and peripheral demyelination with ataxia, dementia.
9
Q

Other demyelinating and dysmyelinating diseases

  • Charcot-Marie-Tooth disease
  • Krabbe disease
A
  • Charcot-Marie-Tooth disease
    • Also known as hereditary motor and sensory neuropathy (HMSN).
    • Group of progressive hereditary nerve disorders related to the defective production of proteins involved in the structure and function of peripheral nerves or the myelin sheath.
    • Typically autosomal dominant inheritance pattern and associated with scoliosis and foot deformities (high or flat arches).
  • Krabbe disease
    • Autosomal recessive lysosomal storage disease due to deficiency of galactocerebrosidase.
    • Buildup of galactocerebroside and psychosine destroys myelin sheath.
    • Findings: peripheral neuropathy, developmental delay, optic atrophy, globoid cells.
10
Q

Adrenoleukodystrophy

A
  • X-linked genetic disorder typically affecting males.
  • Disrupts metabolism of very-long-chain fatty acids Ž–> excessive buildup in nervous system, adrenal gland, and testes.
  • Progressive disease that can lead to long-term coma/death and adrenal gland crisis.
11
Q

Seizures

  • Definition
  • Partial (focal) seizures
    • Definition
    • Types
  • Generalized seizures
    • Absence
    • Myoclonic
    • Tonic-clonic
    • Tonic
    • Atonic
  • Epilepsy
  • Status epilepticus
  • Causes of seizures by age
    • Children
    • Adults
    • Elderly
A
  • Definition
    • Characterized by synchronized, high-frequency neuronal firing.
    • Variety of forms.
  • Partial (focal) seizures
    • Definition
      • Affect 1 area of the brain.
      • Most commonly originate in medial temporal lobe.
      • Often preceded by seizure aura
      • Can secondarily generalize.
    • Types
      • Simple partial (consciousness intact)— motor, sensory, autonomic, psychic
      • Complex partial (impaired consciousness)
  • Generalized seizures (diffuse)
    • Absence (petit mal)—3 Hz, no postictal confusion, blank stare
    • ƒƒMyoclonic—quick, repetitive jerks
    • Tonic-clonic (grand mal)—alternating stiffening and movement
    • Tonic—stiffening
    • Atonic—“drop” seizures (falls to floor); commonly mistaken for fainting
  • Epilepsy
    • A disorder of recurrent seizures (febrile seizures are not epilepsy).
  • Status epilepticus
    • Continuous seizure for > 30 min or recurrent seizures without regaining consciousness between seizures for > 30 min.
    • Medical emergency.
  • Causes of seizures by age
    • Children—genetic, infection (febrile), trauma, congenital, metabolic
    • Adults—tumors, trauma, stroke, infection
    • Elderly—stroke, tumor, trauma, metabolic, infection
12
Q

Headaches

  • Definition
  • Main causes
  • Other causes
  • Cluster headaches vs. trigeminal neuralgia
A
  • Definition
    • Pain due to irritation of structures such as the dura, cranial nerves, or extracranial structures.
  • Main causes
    • Cluster
    • Tension
    • Migraine
  • Other causes
    • Subarachnoid hemorrhage (“worst headache of life”)
    • Meningitis
    • Hdrocephalus
    • Neoplasia
    • Arteritis.
  • Cluster headaches can be differentiated from trigeminal neuralgia based on duration.
    • Trigeminal neuralgia produces repetitive shooting pain in the distribution of CN V that lasts (typically) for < 1 minute.
    • The pain from cluster headaches lasts considerably longer (> 15 minutes).
13
Q

Cluster headache

  • Localization
  • Duration
  • Description
  • Treatment
A
  • Localization
    • Unilateral
  • Duration
    • 15 min–3 hr
    • Repetitive
  • Description
    • Repetitive brief headaches.
    • Excruciating periorbital pain with lacrimation and rhinorrhea.
    • May induce Horner syndrome.
    • More common in males.
  • Treatment
    • Inhaled oxygen, sumatriptan
14
Q

Tension headache

  • Localization
  • Duration
  • Description
  • Treatment
A
  • Localization
    • Bilateral
  • Duration
    • > 30 min (typically 4–6 hr)
    • Constant
  • Description
    • Steady pain.
    • No photophobia or phonophobia.
    • No aura.
  • Treatment
    • Analgesics, NSAIDs, acetaminophen
    • Amitriptyline for chronic pain
15
Q

Migraine headache

  • Localization
  • Duration
  • Description
  • Treatment
A
  • Localization
    • Unilateral
  • Duration
    • 4–72 hr
  • Description
    • Pulsating pain with nausea, photophobia, or phonophobia.
    • May have “aura.”
    • Due to irritation of CN V, meninges, or blood vessels (release of substance P, CGRP, vasoactive peptides).
  • Treatment
    • Abortive therapies (e.g., triptans, NSAIDs) and prophylactic (propranolol, topiramate, calcium channel blockers, amitriptyline).
    • POUNDPulsatile, One-day duration, Unilateral, Nausea, Disabling
16
Q

Vertigo

  • Definition
  • Peripheral vertigo
    • Definition
    • Positional testing –>
  • Central vertigo
    • Definition
    • Findings
    • Positional testing ŽŽ–>
A
  • Definition
    • Sensation of spinning while actually stationary.
    • Subtype of “dizziness,” but distinct from “lightheadedness.”
  • Peripheral vertigo
    • Definition
      • More common.
      • Inner ear etiology (e.g., semicircular canal debris, vestibular nerve infection, Ménière disease).
    • Positional testing Ž–> delayed horizontal nystagmus.
  • Central vertigo
    • Definition
      • Brain stem or cerebellar lesion (e.g., stroke affecting vestibular nuclei or posterior fossa tumor).
    • Findings
      • Directional change of nystagmus, skew deviation, diplopia, dysmetria.
      • Focal neurological findings
    • Positional testing ŽŽ–> immediate nystagmus in any direction
      • May change directions.
17
Q

Sturge-Weber syndrome

  • Type of disorder
  • Definition
  • Findings
A
  • Type of disorder
    • Neurocutaneous disorder
  • Definition
    • Congenital, non-inherited (somatic), developmental anomaly of neural crest derivatives (mesoderm/ectoderm) due to activating mutation of GNAQ gene.
  • Findings
    • Affects small (capillary-sized) blood vessels –>Ž port-wine stain of the face [A] (non-neoplastic “birthmark” in CN V1/V2 distribution)
    • Ipsilateral leptomeningeal angioma [B] Ž–> seizures/epilepsy
    • Intellectual disability
    • Episcleral hemangioma Ž–> increased IOP –>Ž early-onset glaucoma.
  • STURGE-Weber
    • Sporadic, port-wine Stain
    • Tram track Ca2+ (opposing gyri)
    • Unilateral
    • Retardation
    • Glaucoma
    • GNAQ gene
    • Epilepsy.
18
Q

Tuberous sclerosis

  • Type of disorder
  • Findings
A
  • Type of disorder
    • Neurocutaneous disorder
  • Findings
    • HAMARTOMAS:
      • Hamartomas in CNS and skin
      • Angiofibromas [C]
      • Mitral regurgitation
      • Ash-leaf spots
      • Cardiac Rhabdomyoma
      • (Tuberous sclerosis)
      • Autosomal dOminant
      • Mental retardation
      • Renal Angiomyolipoma [D]
      • Seizures
      • Shagreen patches. 
    • Increased incidence of subependymal astrocytomas and ungual fibromas.
19
Q

Neurofibromatosis type I (von Recklinghausen disease)

  • Type of disorder
  • Findings
  • Due to…
A
  • Type of disorder
    • Neurocutaneous disorder
  • Findings
    • Café-au-lait spots [E]
    • Lisch nodules (pigmented iris hamartomas [F])
    • Neurofibromas in skin
    • Optic gliomas
    • Pheochromocytomas.
  • Due to…
    • Mutated NF1 tumor suppressor gene (neurofibromin, a negative regulator of Ras) on chromosome 17.
    • Skin tumors of NF-1 are derived from neural crest cells.
20
Q

von Hippel-Lindau disease

  • Type of disorder
  • Findings
  • Due to…
A
  • Type of disorder
    • Neurocutaneous disorder
  • Findings
    • Cavernous hemangiomas in skin, mucosa, organs
    • Bilateral renal cell carcinomas
    • Hemangioblastoma (high vascularity with hyperchromatic nuclei [G]) in retina, brain stem, cerebellum [H]
    • Pheochromocytomas.
  • Due to…
    • Autosomal dominant
    • Mutated VHL tumor suppressor gene on chromosome 3, which results in constitutive expression of HIF (transcription factor) and activation of angiogenic growth factors.
21
Q

Glioblastoma multiforme (grade IV astrocytoma)

  • Type of tumor
  • Definition
  • Findings
A
  • Type of tumor
    • Adult primary brain tumor
  • Definition
    • Common, highly malignant 1° brain tumor with ~ 1-year median survival.
    • Found in cerebral hemispheres [A].
    • Can cross corpus callosum (“butterfly glioma”).
  • Findings
    • Stain astrocytes for GFAP.
    • “Pseudopalisading” [B] pleomorphic tumor cells—border central areas of necrosis and hemorrhage.
22
Q

Meningioma

  • Type of tumor
  • Definition
  • Findings
  • Treatment
A
  • Type of tumor
    • Adult primary brain tumor
  • Definition
    • Common, typically benign 1° brain tumor.
    • Most often occurs in convexities of hemispheres (near surfaces of brain) and parasagittal region.
    • Arises from arachnoid cells, is extra-axial (external to brain parenchyma), and may have a dural attachment (“tail” [C]).
  • Findings
    • Often asymptomatic
    • May present with seizures or focal neurological signs.
    • Spindle cells concentrically arranged in a whorled pattern
    • Psammoma bodies (laminated calcifications [D])
  • Treatment
    • Resection and/or radiosurgery.
23
Q

Hemangioblastoma

  • Type of tumor
  • Definition
  • Findings
A
  • Type of tumor
    • Adult primary brain tumor
  • Definition
    • Most often cerebellar [E].
    • Associated with von Hippel-Lindau syndrome when found with retinal angiomas.
    • Can produce erythropoietin Ž–> 2° polycythemia.
  • Findings
    • Closely arranged, thin-walled capillaries with minimal interleaving parenchyma [F].
24
Q

Schwannoma

  • Type of tumor
  • Definition
  • Findings
  • Treatment
A
  • Type of tumor
    • Adult primary brain tumor
  • Definition
    • Usually found at cerebellopontine angle [G].
    • Schwann cell origin [H], S-100 (+)
  • Findings
    • Often localized to CN VIII Ž–> acoustic schwannoma (aka acoustic neuroma).
    • Bilateral acoustic schwannomas found in NF-2
  • Treatment
    • Resectable or treated with stereotactic radiosurgery.
25
Q

Oligodendroglioma

  • Type of tumor
  • Definition
  • Findings
A
  • Type of tumor
    • Adult primary brain tumor
  • Definition
    • Relatively rare, slow growing.
  • Findings
    • Most often in frontal lobes [I].
    • Chicken-wire capillary pattern.
    • Oligodendrocytes = “fried egg” cells—round nuclei with clear cytoplasm [J].
    • Often calcified in oligodendroglioma.
26
Q

Pilocytic (low-grade) astrocytoma

  • Type of tumor
  • Definition
  • Findings
A
  • Type of tumor
    • Childhood primary brain tumor
  • Definition
    • Cystic + solid (gross)
    • Benign
    • Good prognosis
  • Findings
    • Usually well circumscribed.
    • In children, most often found in posterior fossa [A] (e.g., cerebellum).
    • May be supratentorial.
    • GFAP (+).
    • Rosenthal fibers—eosinophilic, corkscrew fibers [B].
27
Q

Medulloblastoma

  • Type of tumor
  • Definition
  • Findings
A
  • Type of tumor
    • Childhood primary brain tumor
  • Definition
    • Highly malignant cerebellar tumor [C].
    • A form of primitive neuroectodermal tumor.
  • Findings
    • Can compress 4th ventricle, causing hydrocephalus.
    • Can send “drop metastases” to spinal cord.
    • Homer-Wright rosettes.
    • Solid (gross), small blue cells [D] (histology).
28
Q

Ependymoma

  • Type of tumor
  • Definition
  • Findings
A
  • Type of tumor
    • Childhood primary brain tumor
  • Definition
    • Ependymal cell tumors most commonly found in 4th ventricle [E].
    • Poor prognosis
  • Findings
    • Can cause hydrocephalus.
    • Characteristic perivascular rosettes [F].
    • Rodshaped blepharoplasts (basal ciliary bodies) found near nucleus.
29
Q

Craniopharyngioma

  • Type of tumor
  • Definition
  • Findings
A
  • Type of tumor
    • Childhood primary brain tumor
  • Definition
    • Benign childhood tumor
    • May be confused with pituitary adenoma (both can cause bitemporal hemianopia).
    • Most common childhood supratentorial tumor.
    • Derived from remnants of Rathke pouch.
  • Findings
    • Calcification is common [G], [H] (tooth enamel–like).
30
Q

Herniation syndromes

      1. 4.
A
  1. Cingulate (subfalcine) herniation under falx cerebri
    • Can compress anterior cerebral artery.
  2. Downward transtentorial (central) herniation
  3. Uncal herniation
    • Uncus = medial temporal lobe.
    • Compresses ipsilateral CN III (blown pupil, “down-andout” gaze), ipsilateral PCA (contralateral homonymous hemianopsia), contralateral crus cerebri (ipsilateral paralysis, “false localization” sign).
  4. Cerebellar tonsillar herniation into the foramen magnum
    • Coma and death result when these herniations compress the brain stem (and inhibit respiration).

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